The present invention relates generally to the field of battery systems and, in some embodiments, to battery systems for outdoor power equipment. Outdoor power equipment includes lawn mowers, riding tractors, snow throwers, pressure washers, portable generators, tillers, log splitters, zero-turn radius mowers, walk-behind mowers, riding mowers, industrial vehicles such as forklifts, utility vehicles, etc. Outdoor power equipment may, for example, use an internal combustion engine to drive an implement, such as a rotary blade of a lawn mower, a pump of a pressure washer, the auger of a snowthrower, the alternator of a generator, and/or a drivetrain of the outdoor power equipment. Vehicles include cars, trucks, automobiles, motorcycles, scooters, boats, all-terrain vehicles (ATVs), personal water craft, snowmobiles, utility vehicles (UTVs), and the like. Outdoor power equipment, vehicles, engine driven equipment, engines and other engine related applications are collectively referred to as “equipment.”
Equipment may include an electric starting system in which a starter motor powered by a battery starts the engine. Typically, such electric starting systems also include a user-actuated starter switch (e.g., a pushbutton or key switch) and a starter solenoid. The starter solenoid is the connection between a low current circuit including the starter switch and a high current circuit including the starter motor. To start the engine, the user actuates the starter switch, causing the starter solenoid to close so that the battery provides starting current to the starting motor to start the engine.
A conventional battery system may include a lead-acid battery. The rated voltage and discharge capacity of the lead-acid battery can vary. Typically, the rated voltage for a lead-acid battery used in outdoor power equipment is between 6 volts and 12 volts. Lead-acid batteries are filled with a liquid electrolyte, typically a mixture of water and sulfuric acid. The electrolyte is corrosive. Lead-acid batteries are temperature sensitive, which may result in the engine having difficulty starting or not starting at all in cold weather. Also, a lead-acid battery will degrade over periods of non-use and will gradually lose the ability to provide adequate voltage (i.e., lose charge or become completely discharged—lead acid batteries may lose approximately 1 percent of charge capacity per day of non-use). A lead-acid battery may need to be replaced seasonally, removed from the outdoor power equipment and stored inside, or otherwise maintained or serviced by a user. Infrequent/intermittent use further exacerbates problems inherent to lead-acid batteries. Certain applications (such as outdoor power equipment) that are subjected to extreme temperatures and/or infrequent/intermittent use may cause premature failure of lead-acid batteries.
Lead-acid batteries of a particular rated voltage and discharge capacity have substantially standard dimensions for the spacing between the battery terminals, for the placement of the battery terminals (i.e., top or side mounted terminals), for the location of the positive battery terminal (i.e., left front position or right front position with the terminal side of the battery facing the user), for the size of the battery housing (i.e., height, width, and depth of the housing), and for the mounting points or other structures used to secure the battery to the equipment (e.g., flanges, tie-down points, unobstructed locations to accommodate hold downs, etc.). There are industry standard form factors for lead-acid batteries (e.g., U1, U1R, 22F, 22NF, 26, 26R, etc.). This makes lead-acid batteries of a particular rated voltage and discharge capacity readily replaceable because a replacement battery will fit into the provided space and attach to an electrical system (e.g., via electrical leads connected to the battery terminals) and attach to the equipment (e.g., via hold downs securing the battery to a mounting location) in the same manner as the original battery (e.g., using the same electrical leads and hold downs). A “standard” battery is easily replaceable because batteries of the same size, form factor, terminal location, terminal orientation and terminal configuration can be readily purchased from a variety of sources and such standard batteries are able to be installed as a replacement battery in a piece of equipment without having to modify the mounting location of the original battery or make changes to or replace the wiring leads, hold downs or other components associated with the original battery in order for the replacement battery to make use of the mounting location, wiring leads, hold downs or other components associated with the original battery. For example, the following types of 12 volt batteries are among those considered to be standard for outdoor power equipment: 7U1L, 8U1L, 10U1L, 11U1L, 558MF, and 651MF. Each of these examples and other conventional lead-acid batteries have standard dimensions including a “standard distance between terminals” (center-to-center), a “standard height,” a “standard width,” a “standard depth,” and a “standard cross-sectional area” or footprint (width times depth) that are well-known to those skilled in the arts of batteries and/or outdoor power equipment. For example, for 7U1L, 8U1L, 10U1L, and 11U1L lead-acid batteries, the standard height is 7¼ inches (184 mm), the standard width is 7¾ inches (197 mm), and the standard depth is 5⅛ inches (130 mm). A distance or area is “substantially the same” as one of the standard distances or areas of a standard lead-acid battery when such a distance or area allows a battery or other component having such a distance or area to be readily used in place of the standard lead-acid battery. In some embodiments of the present invention, plus or minus 25% of the distance or area is the outer limit for a distance or area to be considered “substantially the same” as one of the standard distances or areas. In some embodiments of the present invention, plus or minus 20% of the distance or area is the outer limit for a distance or area to be considered “substantially the same” as one of the standard distances or areas. In some embodiments of the present invention, plus or minus 15% of the distance or area is the outer limit for a distance or area to be considered “substantially the same” as one of the standard distances or areas. In some embodiments of the present invention, plus or minus 10% of the distance or area is the outer limit for a distance or area to be considered “substantially the same” as one of the standard distances or areas. In some embodiments of the present invention, plus or minus 5% of the distance or area is the outer limit for a distance or area to be considered “substantially the same” as one of the standard distances or areas. In some embodiments of the present invention, a distance or area the same as one of the standard distances or areas is considered to be “substantially the same” as one of the standard distances or areas.